Supercritical Fluid Extraction technology-basics and application for extraction of neutraceuticals from various sources,

Supercritical Fluid Extraction
Introduction
CONCEPT of SFE
PROPERTIES OF SCF
HISTORICAL BACKGROUND
SUPERCRITICAL FLUID EXTRACTION (SFE)
APPARATUS
COMPONENTS OF SFE
SFE WITH RECYCLING (TRAPPING SYSTEM)
CRITICAL PROPERTIES OF SELECTED SUBSTANCES
OBJECTIVES FOR COMMERCIALIZATION
MULTIPLE SOLUTES IN SFE
ADVANTAGES of Sfe
LIMITATIONS
PRECAUTIONS
APPLICATIONS

1. Supercritical Fluid Extraction Prepared By: MOHAMMAD KHALID (Assistant Professor ) Krishna Pharmacy College, Bijnor (UP)

2. content Introduction CONCEPT PROPERTIES OF SCF HISTORICAL BACKGROUND SUPERCRITICAL FLUID EXTRACTION (SFE) APPARATUS COMPONENTS OF SFE SFE WITH RECYCLING (TRAPPING SYSTEM) CRITICAL PROPERTIES OF SELECTED SUBSTANCES OBJECTIVES FOR COMMERCIALIZATION MULTIPLE SOLUTES IN SFE ADVANTAGES of Sfe LIMITATIONS PRECAUTIONS APPLICATIONS 29 April 2020 Krishna Pharmacy College, Bijnor 2

3. Introduction Supercritical Fluid Extraction (SFE) is a eco-friendly alternative of extraction replacing organic solvents. In SFE use of Supercritical fluids (SCF’s) like supercritical CO2 as solvent is there. SCF are increasingly replacing organic solvents because of regulatory and environmental pressures on hydrocarbon and ozone depleting emissions. SCF helps in extraction of natural products of wide range of polarities. 29 April 2020 Krishna Pharmacy College, Bijnor 3

4. CONCEPT Cagniard de la Tour discovered critical point (CP) in 1822. CP of pure substances is defined as the highest temperature and pressure at which the substances can exist in vapour- liquid equilibrium. At temperature and pressure above this point, a single homogenous fluid is formed, which is known as SCF. SCF is heavy like liquid but has penetration power like gas. SCF’s are produced by heating a gas above its critical temperature or compressing a liquid above its critical pressure but in this molar volume remains same irrespective of original form( liquid or gas). 29 April 2020 Krishna Pharmacy College, Bijnor 4

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6. PROPERTIES OF SCF Physical and thermal properties of SCFs are in between pure liquid and gas, hence can also be known as ‘Compressible liquids’ or ‘dense gases’ Changes in properties are for a SCF are as follows: Liquid like densities (100-1000 times greater than gases) Diffusivities higher than liquids (10-3 and 10-4 cm2 / s) Good solvating power – Reduction in surface tension Low viscosity (10-100 times less than liquid) Gas like compressibility properties Therefore they posses high penetrating power 29 April 2020 Krishna Pharmacy College, Bijnor 6

7. HISTORICAL BACKGROUND Solvent properties of SCF were first reported well over 100 years ago in 1879 by Hannay and Hogarth, (measured solubility of inorganic salts in supercritical ethanol) Since 1980s and 1990s SCF has been used in several industrial processes. 29 April 2020 Krishna Pharmacy College, Bijnor 7

8. Carbon dioxide as SCF Carbon dioxide: M ost commonly used SCF L ow critical parameters (31.1°C, 73.8 bar) L ow cost Low density Low viscosity Non-toxicity . Abundant source Eco friendly 29 April 2020 Krishna Pharmacy College, Bijnor 8

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10. Continue…… Supercritical fluid extraction is the process of separating one component from another (the matrix) using supercritical fluids as the extracting solvent. Steps: Introduction of feed into extractor (solid feed) or extractor in modified column either co-currently or counter currently Formation of mobile phase: mixing of solutes with supercritical fluid. Exposure of mobile phase to pressures (50-500 atm ) and temperatures (ambient to 300°C) near or above the critical point for enhancing the mobile phase solvating power. Isolation of dissolved solute by precipitation Eg . CO2 in vapour form is compressed into a liquid before becoming supercritical and then extraction takes place. 29 April 2020 Krishna Pharmacy College, Bijnor 10

11. APPARATUS Simple diagram of supercritical extractor 29 April 2020 Krishna Pharmacy College, Bijnor 11

12. diagram of supercritical extractor 29 April 2020 Krishna Pharmacy College, Bijnor 12

13. COMPONENTS OF SFE Fluid reservoir (gas cylinder in case of CO2 ) Pump – Reciprocating pump – Syringe pump (pulse-free flow at large range of flow rates) Extraction cell/column (stationary phase) Usually stainless steel Chamber or vessel in compartment Capable of withstanding high pressure (300-600 atm ) [for solids] Open tubular capillary columns or packed columns [liquids] 29 April 2020 Krishna Pharmacy College, Bijnor 13

14. Continue…. Restrictor Maintaining pressure change inside the extraction vessel Two types- fixed (linear restrictor, tapered desire, integral restrictor, ceramic frit restrictor, metal restrictor) Variable (variable nozzle, back pressure regulator ) Collector (trapping system) Detectors (flame ionization detector of gas chromatography) 29 April 2020 Krishna Pharmacy College, Bijnor 14

15. SFE WITH RECYCLING (TRAPPING SYSTEM) Recycling of SFE can be done- 1 . Reduction of pressure - SCF unable to dissolve the solute, separation of sold under gravity and the gas at low pressure is compressed back to the supercritical conditions. 29 April 2020 Krishna Pharmacy College, Bijnor 15

16. Continue… Reduction of temperature - solute drops and recovery of solvent without recompression Pumping SCF to expansion tank - where it becomes gas resulting in very less solubility i.e. separation of solute. Spent gases are then recompressed and recycled. Heat exchangers are used to maintain temperature and prevent excessive cooling at throttling valve called as Joule-Kelvin effect. 29 April 2020 Krishna Pharmacy College, Bijnor 16

17. Continue…. Pumping SCF to expansion tank 29 April 2020 Krishna Pharmacy College, Bijnor 17

18. CRITICAL PROPERTIES OF SELECTED SUBSTANCES 29 April 2020 Krishna Pharmacy College, Bijnor 18

19. MODES OF SFE STATIC EXTRACTION MODE (steady state) DYNAMIC EXTRACTION MODE (non-steady) Sample matrix is soaked in a fixed amount of supercritical fluid Can be compared to a teabag in a cup of water. Supercritical fluid continuously passes through the sample matrix Analogous to coffee maker 29 April 2020 Krishna Pharmacy College, Bijnor 19

20. Continue.. Sample Matrix Parameters that influence SFE : – Particle size and shape – Surface area and porosity – Moisture content – Changes in morphology – Sample size – Extractables level The parameters effect on solubility: – The vapour pressure of the component – Interaction with the supercritical fluid – Temperature, pressure, density and additives 29 April 2020 Krishna Pharmacy College, Bijnor 20

21. OBJECTIVES FOR COMMERCIALIZATION Separation of multiple solutes (as solubility of solute in supercritical solvent may be a function of temperature and pressure) Use of entrainers /modifiers an enhance versatility and efficiency. Eg . CO2mixed with 1-10% of methanol to solubilise more polar solutes. 29 April 2020 Krishna Pharmacy College, Bijnor 21

22. MULTIPLE SOLUTES IN SFE Separation of solutes is by using a two-stage process. Method First extraction: similar to single stage (soluble-dissolved, less soluble- left) Second extraction : dissolution of the remaining solute in the solid in the solvent will result in the isolation 29 April 2020 Krishna Pharmacy College, Bijnor 22

23. Continue….. 29 April 2020 Krishna Pharmacy College, Bijnor 23

24. ADVANTAGES of SFe Elimination of organic solvents i.e. reduces the risk of storage. Rapid (due to fast back-diffusion of analytes in the SCF reduces the extraction time since the complete extraction step is performed in about 20 min) Suitable for extraction and purification of compounds having low volatility present in solid or liquid Susceptible to thermal degradation (low operating conditions) 29 April 2020 Krishna Pharmacy College, Bijnor 24

25. Continue….. Complete separation of solvent from extract and raffinate Continuous process Low handling cost Solvent recovery is easy Versatile and efficient (use of co-solvents and co-solutes) 29 April 2020 Krishna Pharmacy College, Bijnor 25

26. LIMITATIONS Prolonged time (penetration of SCF into the interior of a solid is rapid, but solute diffusion from the solid into the SCF). Modeling is inaccurate Scale is not possible (due to absence of fundamental, molecular-based model of solutes in SCF) Expensive Consistency & reproducibility may vary in continuous production 29 April 2020 Krishna Pharmacy College, Bijnor 26

27. PRECAUTIONS Adequate contact time ( for penetration of solvent into solid particles and diffusion of solute from inside the solid particles to solvent) Equilibrium should be achieved ( i.e. proper flow of solvent such that concentration of dissolved solutes in the solvent phase will be below the solubility of solute in solvent) 29 April 2020 Krishna Pharmacy College, Bijnor 27

28. APPLICATIONS Food science Fat and oil samples in meat, egg, meals, chocolate, dairy products, seeds and food snacks , Natural products Flavors & spices of ginger, eucalyptus, soyabean , coffee, soybean, basil, lime peels, potato chips, popcorn By-products recovery Fruit and vegetable waste 29 April 2020 Krishna Pharmacy College, Bijnor 28

29. REFERENCES Sairam , P., Ghosh , S., Jena, S., Rao , K.N.V. and Banji , D. (2012) Supercritical Fluid Extraction (SFE)-An Overview Asian J. Res. Pharm. Sci.; Vol. 2: Issue 3, Pg 112-120. Das , S. supercritical fluid extraction, module 10. NPTEL. Jonin , T.M., Adjadj , L. P and Rizvi , S.S. Food Engineering. Vol III. Encyclopedia of Life Suport System (EOLSS ). Toledo , Supercritical fluid extraction. Chapter Extraction. Third Edition. pp 528-531 https://www.slideshare.net/NandhuLal/super-critical-fluid-extraction?qid=a3bbfead-c35f-4f66-81ba-ad4daed2b9e7&v=&b=& from_search=9 https://www.slideshare.net/jasminekaur144/supercritical-fluid-extraction-81381737?qid=a3bbfead-c35f-4f66-81ba-ad4daed2b9e7&v=&b=&from_search=16 29 April 2020 Krishna Pharmacy College, Bijnor 29

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